Whale fossil records show large-scale evolutionary changes from their ancestors to their descendants. By inspecting one particular ankle bone, the astragalus, in whale fossil, its shape and structure end a long standing dispute. The whale evolved from artiodactyls and not mesonychids.
Fossil evidence shows relations of whale ancestors and their decendents because fossil remains and the skeletons of common day whales have similar atributes. While some of the physical features are different in the decendents, they are still very similar. The differences could be with the blubber thickness or body size.
